


Pray in the Dark

by quicksilverdeancas (quicksilvermalec)



Series: Sastiel Big Bang 2020 [2]
Category: Supernatural
Genre: Alternate Universe - Canon Divergence, Alternate Universe - Soulmates, Angst, Blood, Blood and Violence, Dean Winchester Bears the Mark of Cain, Death, Divorce, Drunk Sam Winchester, Heavy Angst, Hurt Castiel, Hurt No Comfort, Hurt Sam Winchester, Mark of Cain (Supernatural), Murder, Other, Possibly Unrequited Love, Sad Castiel, Sad Ending, Sad Sam Winchester, Season/Series 09, Soulmate-Identifying Marks, Suicide, Unrequited Love, Wedding, enjoy... ?, i think y'all might cry js :/, this story is pretty dark
Language: English
Status: In-Progress
Published: 2020-09-22
Updated: 2020-09-22
Packaged: 2021-03-08 02:34:51
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence, Major Character Death
Chapters: 1
Words: 3,599
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26598409
Author URL: https://archiveofourown.org/users/quicksilvermalec/pseuds/quicksilverdeancas
Summary: Sam is desperately, hopelessly, miserably in love with an angel. His problem? The angel is in love with his brother, and he doesn't have it in him to make any attempt to break up their relationship.Sam never even learns that his angel is his soulmate.
Relationships: Castiel & Sam Winchester, Castiel/Dean Winchester, Castiel/Sam Winchester, Dean Winchester & Sam Winchester
Series: Sastiel Big Bang 2020 [2]
Series URL: https://archiveofourown.org/series/1928239
Comments: 22
Kudos: 47
Collections: Sastiel Big Bang 2020





	Pray in the Dark

**Author's Note:**

  * For [nathyfaith](https://archiveofourown.org/users/nathyfaith/gifts).



> This work was created for the Sastiel Big Bang with accompanying art by the gorgeous and glorious nathyfaith.
> 
> Blah blah disclaimer, blah blah Kripke, blah I don't own this, blah blah blah.
> 
>  **WARNING**  
>  I am warning again for suicide, blood and gore, homicide, and death. _This is not a happy story._ Continue at your own risk.

Some people have mundane things. “Did you get the mail?” “How was work today?” “Where are my keys?” That’s painful because people just simply don’t know when it’ll come. Every time the simplest, most everyday things happen, their blood goes cold.

Some people have things like “did you do the homework?” “My mom said it was okay.” “This is my least favorite class.” That hurts worse for their parents, because they know it’ll come early and they can’t protect them, and while it’s one thing to love and to lose, it hurts worse to never know at all.

Still others have words like “can I get your phone number?” “What’s your name, hon?” “That’s 14.46 at the next window.” And it’s quite possibly the cruelest thing of all to know that you’ll meet them once and never know them at all.

But Sam has spent his entire life tortured by the words **He’s the only one who understands.**

He wishes he knew what they were about. He wishes he knew who his soulmate was or why they say those words but he’s heard them a fair number of times in his life, always with someone he’d spoken to again later.

This is the story of how Sam came to realize who his soulmate was, and subsequently lose them.

~~

It starts when an angel falls into bed with his brother. Well… _another_ angel. Dean’s already had sex with at least two.

Sam finds them just minutes post-coitus, spread out on the couch naked and barely covered with the blanket over their waists. He walks into the den and his heart breaks, so he covers it with disgust and mild disdain and thinly veiled support.

“Jesus,” he mutters, just walking past them into the kitchen. “At least the next time you do this, don’t do it on the couch. This is a communal space and I still live here, okay guys?”

Dean looks relieved and relaxed, and grins at him. “Yeah,” he replies. “Thanks, Sammy.”

Sam forces a soft smile at them. “Anytime. But seriously, get some clothes on.” He glances in the pantry before scoffing and fishing around in Dean’s discarded jeans for the keys to the Impala. “I’m getting fast food drive thru. Text me what you want from Arby’s.”

Dean scoffs but doesn’t argue. “Alright, see you later.”

Sam smiles and watches him relax against Castiel. It’s amazing and makes him happy to see Dean so comfortable and _himself_ with someone. Sam’s never seen him this exposed and vulnerable. If Cas is what it takes, Sam will swallow his feelings for his brother’s sake.

Dean closes his eyes and curls closer, resting on Cas’s chest. Sam stands in the doorway, just watching them, for a long moment before he opens the door and disappears to get them dinner.

By the time he gets back, they’re decent and they’ve cleaned themselves up. He can almost forget the very vivid mental images he has of what they may or may not have done to each other.

~~

Sam supposes the next part is when Cas comes to him with an interesting proposition.

“I would like to marry your brother,” he says bluntly. Sam stares at him.

“Uh…” he says. “Okay. Cool. You’re telling me this because why?”

Cas bites his lip. “I understand it is customary for one to ask their intended’s family for their permission and or approval before proposing.”

Sam snorts. “Not anymore. That was about forty to fifty years ago, at least. And usually that’s a man proposing to a woman, and he’d normally ask her father. Dean’s not a woman, he’s a male-identifying person, and you’re not a man, you’re a multidimensional wavelength of celestial intent shaped vaguely like a man, and I’m not Dean’s father, I’m his younger brother, so really none of that applies here.”

Cas purses his lips in the way that some people do when they’re trying very, very hard to keep from laughing. “Very well, Sam. Would you mind helping me pick out a ring, at least?”

 _Yes,_ Sam wants to say. _Yes, I would mind so very incredibly much, because the very thought of you being with Dean tears me into pieces in a way that I never thought I could feel. Because somehow, despite being tortured and raped in the Cage for thousands of years, I have never felt such intense pain as I have in the months since you and Dean inadvertently revealed your relationship to me. I would mind, Castiel, because_ I’m _in love with you, too. Dean isn’t the only Winchester to fall for our angel._

But he can’t say any of those things. Because he’s a good and faithful little brother, not to mention he can’t corrupt a literal angel that way, not as an upstanding Christian, and he refuses to destroy their relationship when he loves them both so incredibly much.

So he doesn’t say those things, and instead he forces a smile and says “yeah, I could do that.”

Castiel lights up like the sun peeking out from behind a cloud, and Sam knows he made the right decision.

~~

They go ring shopping together that weekend. In honesty, it makes Sam feel a little pathetic. He’s out and about with his best friend whom he’s secretly madly in love with helping him buy a ring to propose to someone else. It makes him feel sick. He’s miserable.

But if having Dean Winchester as his one active parental figure during the most formative years of his life taught him anything, it’s how to play through pain, repress your emotions, and convince everyone around you – including yourself – that you’re totally fine at all times.

So Sam does.

His faked enthusiasm must be pretty believable because Cas buys it, and so does the cashier. They pick out two options – platinum and white gold – and they’re looking at them both side by side. “The white gold is more easily damageable, but it’s lighter,” she explains to them. “The platinum is heavier and more expensive, but also more durable.”

Sam glances at Cas. “Well, money is a nonissue for us, so honestly? I think you should go with the platinum.”

Cas smiles. “I would be inclined to agree. Thank you, Sam.”

Sam nods. “You’re welcome,” he murmurs softly. The cashier smiles at them.

“I don’t see a lot of couples ring shopping together,” she tells them as she rings up their purchase. “It’s actually really sweet that you’re choosing your rings together.”

Cas shakes his head. “No, Sam and I are not a couple. I am hoping to end up marrying his brother.”

Her face instantly pales. “Oh,” she manages. “It’s just… you seem so… Are you sure you’re not soulmates?”

Sam purses his lips. “Cas doesn’t have one, and… how can anyone be sure? No one really knows if they’ve met their soulmate until they die or walk out of your life forever.”

She nods. “Of course. Silly of me to ask. Here are the rings, anyway, and, uh… well, I hope your brother says yes.”

Cas takes them from her graciously. “Thank you,” he manages. “I hope his brother says yes as well.”

~~

Dean says yes.

~~

More accurately, he screams it like a girl being proposed to on a fancy dinner date in some clichéd heterosexual romantic comedy or chick flick. Sam can hear him from the other end of the Bunker.

It would be cute. If Sam’s heart wasn’t currently lying on the floor smashed into a million pieces by a sledgehammer.

~~

And then comes the part that really ties the bow on all the beautifully horrifically miserable events of the past several months. Dean and Cas ask Sam to officiate their wedding.

And Sam… Sam is an idiot, and a guilty one at that. So Sam agrees.

He gets ordained online, Dean picks up the marriage license from the county clerk’s office, and they’re legally married in the library of the Bunker.

Sam is only a little ashamed to admit he cries himself to sleep that night.

But Cas and Dean are happy. He keeps reminding himself of that. Cas and Dean are together, and happy, and that’s all he’s ever wanted for his friends, no matter what his personal feelings might be. No matter if those personal feelings are partially feeling his entire being torn in half every time he sees them together and partially wishing he could tear his brother in half every time he sees them together. It doesn’t matter. He has to remember that.

It doesn’t matter. It will never matter. He will be ~~miserable~~ happy on his own and Dean and Cas will be happy together.

The world spins on. Sam’s heart remains broken.

~~

The turning point, the thing that simultaneously fixes everything and makes it a thousand times more painful, comes on Dean and Cas’s first wedding anniversary.

Sam makes them a video, because he doesn’t know what else to do for them, and then he disappears to let them have loud sex while he gets drunk alone.

Cas finds him around two in the morning, which Sam supposes is technically no longer their wedding anniversary, but he doesn’t really care because he’s drunk and tired and he’s been awake for twenty-seven hours and he wants to die. But Castiel is here, his angel, the angel he’s been in love with practically since that first far-too-long handshake. And he’s happy, because he’s always happy with Cas, but he’s depressed, too. Because Cas belongs to someone else. Cas always has and always will belong to Sam’s brother, and never to him.

Dean doesn’t have a soulmate. Sam’s happy that he found someone else without a soulmate who makes him happy. Sam’s happy that Cas managed to somehow be at peace with himself, to love someone so deeply and truly that Sam’s measly, weak, moronic human brain could never comprehend. And he knows it’s selfish to wish that he were the one being loved like that.

He’s torn apart. He can’t fix this.

And that is how Castiel finds him, laying on the floor, drunk out of his mind and depressed enough to put a bullet in his mouth if he had the energy to lift his gun.

Cas sits down on the floor next to him. “Are you alright, Sam?” he asks quietly. Sam shakes his head.

“What part of this… gives you the okay that I’m idea.” He frowns. “Idea that I’m okay. Yeah. That.”

Cas purses his lips. “Well, at least you’re being honest, I suppose. What are you feeling right now, Sam?”

Sam laughs bitterly. “Nothing,” he confesses. “I feel… _nothing_. I’m broken and… and cruel… and mean. I suck. You should- you should hate me, Cas. I’m the worst.”

Cas shakes his head. “No, Sam, I will never hate you. You are my best friend.”

“I don’t wanna be your best friend!” Sam shouts, slurring wildly. “I don’t wanna.” He sounds a little like a petulant child, but he doesn’t particularly have an issue with that. It’s just his alcohol-blurred brain anyway.

Cas gently pries the bottle from his hands and sets it on the floor, far out of his reach. “What’s wrong, Sam?” he asks.

“Why did you marry Dean?” Sam wonders aloud. “What- why?”

Cas sighs. “Well… I married your brother because he’s hotheaded and passionate and he cares a lot about people even if he doesn’t show it. I married him because I’ve seen his soul and it’s one of the most beautiful things in the world. I married him because he needed someone to be close to him, to help him heal from everything that’s happened and he needed someone besides you because the two of you… you escalate each other. I married him because I was in love with him, Sam.”

Sam sighs and stands up. “I’mna go to bed,” he mumbles.

“I’ll help you,” Cas offers, holding him steady and leading him toward his bedroom. Sam leans subconsciously into the comforting touch and the warm promise of more, drawing them from Cas as long as he could until Cas inevitably leaves him again.

It’s just that… Sam knows he will never be enough. He’ll never be enough for Cas – Cas who wants Dean, who wants his green eyes and his bowlegs and his symmetrical face and his gender-conforming male normality. Cas who wants Dean in all his fucked-up, dysfunctional glory, who wants to _heal_ him, because Sam can’t do it because – he’ll never be enough for Dean, either – Dean, who is ruined in so many ways, who was abused and maltreated, who hated himself all his life. Dean who believes he is broken in so many ways that cannot be fixed, Dean who resists Sam’s every attempt to help him because all Sam has ever wanted was for Dean to feel okay, even just for a little while, because Dean never takes anything for himself and that’s why Sam has to sacrifice the angel to him, because Cas is the one thing Dean will accept for his own wellbeing and Cas can help him in all the ways Sam will never be good enough to. Sam can’t help him.

Sam will never be good enough, and he’s long since made his peace with that.

But as Cas deposits him in his bed, walks away from it, Sam calls out his name, makes him pause in the doorway and turn. “Yes?” he asks patiently, always so patient, so _good_ , putting up with Sam and all his bullshit on his anniversary when he should be with Dean, should be celebrating how happy he is with the man that isn’t Sam. Sam hates himself for this, hates himself for everything. The guilt is overwhelming.

“It’s because he understands you, isn’t it?” he asks. It’s a miracle he can get through that full sentence.

Cas nods sadly. “Dean is…” he trails off, staring at the wall. “He’s the only one who understands.”

He closes the door behind him, and Sam is far too drunk and far too close to sleep to figure out why those words seem so goddamn familiar.

~~

Sam wakes up screaming.

~~

Sam wakes up with one of only two people in this world still living that he really loves standing over him, a blade pressed to his throat. Sam screams and looks up at him and pleads for mercy, and Dean’s cold, emotionless eyes don’t soften in the slightest.

“Dean,” Sam sobs. “Please. It’s me, I’m your brother, I love you. Please…”

Dean doesn’t say anything. He just lifts the First Blade above his head and plunges it deep into Sam’s chest.

The light dies in Sam’s eyes, and the second it goes out, Dean is himself again.

Just a second too late.

~~

Dean will never forgive himself, Cas knows. When he returns to the Bunker from his pie run he finds Dean vomiting into the toilet, and he drops everything to be at Dean’s side. “Dean,” he whispers urgently. “Dean, are you alright? What happened, are you sick?”

Dean wipes his mouth on his sleeve and looks at Cas through empty eyes laced with horror. “I killed him,” he whispers. “He’s dead, Cas, I killed him. This thing, the Mark… I didn’t even know what I was doing. It was like I just woke up, and I was in his room, and he was dead.”

It takes Cas another couple seconds to figure out what he’s talking about. His heart drops into his stomach. “Sam?” he croaks. His voice is low and horrified.

“I lost control,” Dean whispers, and then he lets out a choked, miserable sob, a horrible sound from deep in his chest that breaks Cas’s heart. He never wants to hear it again.

Cas pulls him into his chest, holds him close, and doesn’t try to say anything. He knows there is nothing in all the world that anyone can say that will make this better. Nothing will ever fix what Dean has lost, and a death by the First Blade… that’s irreversible. They’ll never get him back.

They go back to him, to find him, and they peel off his shirt to clean him up, to put him in a new one. But Cas’s heart sinks lower, from the pit of his stomach into the floor, because in a delicate scrawl across Sam’s left bicep, where he always used to wear his armband, are the words **He’s the only one who understands.** But they’re not black like most people’s words. They’re blue.

They’ve already been said.

 _Blue like my eyes,_ Cas thinks, and he thinks back to the night before, the last words he’d said to this friend, and he wonders if Sam loved him that way. _Why wouldn’t he tell me?_ he thinks, but even as he thinks it he knows the answer.

He will never be the same again. He and Dean will never be the same.

He closes his eyes, extends his wings to fly into the city, to fly _anywhere else_ , and a set of Enochian words float across his vision.

His heart must be in the center of the Earth now.

He pulls one large, invisible, dark wing in front of himself and sees them, seared into his feathers.

**It’s because he understands you, isn’t it?**

“I thought I didn’t have one,” Cas breathes. “I always thought I didn’t have a Gracemate.”

He does.

He does, and it’s the brother of the man he married. He does, and he pushed him away again and again, repressed his feelings for him because he swore to be monogamous to Dean and he’s not an angel who breaks his promises. He does have a Gracemate, and he promised himself to the wrong person, gave his heart to them, committed himself fully to Dean when Sam was _right there_.

If he could have had them both…

But there’s no use in thinking that way now, not when Sam is gone and there is nothing Castiel can do to change that. He doubts it will stop him from thinking it, though, because knowing too late is one of the cruelest things in the world.

~~

They give Sam a hunter’s funeral. They burn him behind the Bunker, in the woods near where he used to love to jog. Cas remembers his favorite places.

They don’t take any cases for a while. Instead, they go across the country on an unofficial Goodbye, Sam Winchester tour. They visit his favorite diners, play his favorite songs, find his favorite spots in nature in all fifty states. They finish back in Kansas, they go back to Lawrence, and they see the house. Cas can’t bring himself to touch Dean at all, and Dean doesn’t ask.

Cas waits a full week after they return to the Bunker.

“Dean,” he says quietly. “Dean, we need to talk.”

Dean sits down at the table. “Alright,” he says softly. “What about?”

“About Sam,” Cas replies. “About… us.”

“What about us?” Dean asks, his guards instantly up. Cas takes a shaky and completely unnecessary deep breath.

“I can’t stay married to you,” he replies softly.

Dean’s face visibly pales and Cas thinks idly that Dean is wearing the same expression he himself wore just over a year ago when Dean told him he couldn’t continue to live in the Bunker.

“What?” Dean asks weakly. “I’ve lost _so much_ and now you’re going to take my marriage?”

“Just listen to me, Dean,” Cas implores. “The words on your brother’s arm, did you see them?”

Dean swallows and nods. “‘He’s the only one who understands’?” he recalls. Cas casts his eyes down to the floor.

“Those were the last words I said when I left Sam’s room that night. Before—” _you killed him_ “—he died. And now… I have the words Sam said to me right before that tattooed on my wings in Enochian. Dean, your brother and I were soulmates. And I don’t feel right continuing in this relationship with you. I feel as though I am dishonoring his memory.”

“Did you love him?” Dean asks abruptly.

Cas glances at him and slowly nods.

“Then why were you with me? You shoulda been with him.”

“Because… because I loved you too. And I never thought Sam would love me. I never thought I had a Gracemate, either, until Sam died. I thought you and I were more compatible, as two beings without mates.”

“But you would have made Sam happy. I didn’t have to fall in love with you,” Dean snarls, sounding angry. “I wasn’t fated to. But Sam was. Instead of letting us be happy you just strung us both along.”

“I didn’t know!” Cas insists.

“I don’t care,” Dean growls. “Get out of my sight.”

~~

Within three months, they’re divorced.

Dean never apologizes for the things that he said to Cas that night. Not even in the note on his bedside table the night Cas finds him hanging from the ceiling in his room, a rope around his neck.

And then Cas is alone again, to wander this strange, cruel world without his two closest friends to guide him.

This is how it was intended, he knows. He was never meant to fall for two human men. The fact that he did just proves that he cannot be trusted with his own destiny.

But if this is how he was created, why does it feel so unjust?

If he was meant to live this way, why is he so lonely?

He wonders. Will he ever feel happy again?

Will he ever feel anything again?

**Author's Note:**

> *heavy sigh* send the bill for emotional damages to my office 😝
> 
> Thank you all for going on this ride with me. It's been really exciting and I'm so happy to share this with all of you.
> 
> (And keep an eye out for a part two coming up at some point 😉)
> 
> So much love,  
> -Dean


End file.
